Fixed - C3900-universalk9-mz.spa.157-3.m8.bin

show flash: dir flash:

Before upgrading or migrating your Cisco 3900 router to C3900-universalk9-mz.spa.157-3.m8.bin , you must verify that your hardware meets the minimum resource allocations required by this specific version. Failure to do so will cause the router to crash or enter a continuous boot loop. Memory Requirements C3900-universalk9-mz.spa.157-3.m8.bin

(common attack vector): no vstack no vstack setup show flash: dir flash: Before upgrading or migrating

Check that the file transferred successfully without corruption: C3900-universalk9-mz.spa.157-3.m8.bin

If the router encounters a corrupted file or invalid configurations during the upgrade, it will drop into the ROM Monitor (ROMMON) CLI environment ( rommon 1> ). Follow this recovery procedure to load the system back up over the network.